Contents

Port Location

Evora

On a cable that hangs down under the dash on the drivers side or (passenger side on left hand drive cars).

Fixed to the aluminium crossmember, pointing down, just past the point where the dash leather stops in the footwell, you should be able to feel it without stretching forward too much from the driving position.

DIY

OBDII Connector, S2 111R

OBDII Connector, S2 Exige

On the S2 Elise it is quite simple to connect to the cars ECU yourself.

Until 2008 all S2's can be queried using the ISO 9141-2 OBD II protocol for the OBD required error codes and results.
From 2008 onwards CAN is the only permitted OBD2 protocol.

All S2 variants also have a CAN bus connection on the same diagnostic connector.

For the Rover powered S2 variants the CAN bus is only connected to the engine ECU and used by the Lotus scan tool to reflash/upgrade the ECU and obtain the ECU dump information at the first service.

The dash unit still uses discrete inputs for the various gauges and information readouts, either connecting directly to sensors or using PWM signals from the ECU.

The Toyota powered S2 (111R, Fed-Elise, Exige2) also connects the CAN bus (running at 1 megabit/s) to the dash unit and does away with most of the discrete inputs to the dash unit, RPM, speed, MIL/CEL, coolant temperature and fuel level are supplied via the CAN Bus, the rest are discreete inputs.

The ScanTool3 provides the ECU reflash and DUMP via the K line, using the L line as an enable latch, the CAN bus is not used for reflashing or ECU dump, though it can be used by Lotus with their internal EFi supplied mapping tools.

OBD-II codes

OBD-II codes consist of a number of parts. Here is a sample OBD2 code:

P0171

Here is a breakdown of what each digit of the code means:

First Character - System
The first character identifies identifies the system related to the trouble code.

P = Powertrain

B = Body

C = Chassis

U = Undefined

Second Digit - Code Type
The second digit identifies whether the code is a generic code (same on all OBD-II equpped vehicles), or a manufacturer specific code.

0 = Generic (this is the digit zero -- not the letter "O")

1 = Enhanced (manufacturer specific)

Third Digit - Sub-System
The third digit denotes the type of sub-system that pertains to the code

1 = Emission Management (Fuel or Air)

2 = Injector Circuit (Fuel or Air)

3 = Ignition or Misfire

4 = Emission Control

5 = Vehicle Speed & Idle Control

6 = Computer & Output Circuit

7 = Transmission

8 = Transmission

9 = SAE Reserved

0 = SAE Reserved

Fourth and Fifth Digits
These digits, along with the others, are variable, and relate to a particular problem. For example,a P0171 code means P0171 - System Too Lean (Bank 1).